VOCAL BEHAVIOUR IN THE KITTIWAKE GULL (Rissa Tridactyla): A Summary and Progress Report

DR. D . D AN IELS Departme nt o f Psycho logy

Washingto n Singer Laborato ri es Unive rsity of Exete r

Exeter EX4 4QG

Because of its unique geological structure a nd geographical location , Lundy provides an ideal habitat fo r many sea birds which fo llowing a winter at sea return to land during the Spring to breed . Most visitors to Lundy are aware of the A lcidae (the Razorbill s, Guillemots, Puffins) that surround Lundy at their particular times a nd if o nly because of their raucous voca l disputes , the Laridae too make their presence known o n Lundy during the early Spring a nd Summer. Less noted breeding visito rs a re the Proce llariidae , the Fulmars and the Shearwaters. However , it is with th e vocal be havio ur of one of the gull species Rissa tridactyla or the Kittiwake , that this article is concerned .

The fir st published study o f Kittiwake be hav iour was published by Paludan (1955) who studied a co lony of Kittiwakes o n the island o f Tyvholm just off the coast of Denmark . The colony nested on the ground ve ry much as does the He rring G ull (Larno argentatus). However , the Kittiwa kes of Lundy inhabit the sheer p recipito us cliffs of the West and North East coasts of Lundy, ranging from Je nny's Cove aro und to Puffin Slope. Cullen (1957) in her erudite study of similar breeding habitats o n the Farne Isla nds , argued that the ancestral breeding habitat of the Kittiwake was the grassy slopes above the sea and it was o nly as a result of severe pressure from predatio n that the Kittiwake was fo rced to colonise the inhospitable narrow ledges of north-facing cliffs . Culle n observed that the breeding behav iour of the cliff nesting Kittiwake differed significantly from the behavio ur of ground-nesting gull s a nd suggested that the changes no ted were behav ioural adaptations which ensured a continued presence on the ledges. Pa re nta l behaviour and behavio ur d uring courtship in cliff nesting Kittiwakes was less de mo nstrati ve and , there fore, less like ly to dislodge partners, nests, eggs and young chicks from the tiny ledges. McLanna han (1973) has discovered that cli ff-nesting Kittiwakes have undergone anatomical changes in the feet ensuring greate r adhe re nce to the ledges.

In his earlie r study Pa ludan had described eight (possibly nine) voca l ca ll s and associated be havioural displays in ground-nesting Ki ttiwakes , and Cullen had little to add regarding voca l be haviour in cliff-nesting Kitt iwakes. Interest in the vocal behavio ur of the Kittiwakes o f Lundy developed through my staying on Lundy as a visitor during the summer and thro ugh organising unde rgraduate fi eld courses in the Spring. Gradually, following many ho urs o f o bserva tion and reco rding it seemed like ly that the cliff-nesting Kittiwake had more discern ably diffe re nt calls than its ground nesting conspecific. A serio us inves tigation o f Kittiwake vocal behavio ur was comme nced in 1979 and has been supported financiall y by the Unive rsity of Exe ter a nd by the Lundy Fie ld Socie ty. To date , fourteen ca lls have been distinguished , twelve o f which it has been poss ible to record fo r subseq uent spectrographic analys is in the laborato ry. Ma ny o f these calls diffe r from each other in both temporal a nd tona l aspects (Daniels & Hea th , 1984). Thus it appears that the vocal repertoire of the cliff-nesting Kittiwa ke has d iversified from the more limited repe rto ire o f ground-nesting Kittiwake. Zahavi (1982) cogently argues that voca l behavio ur is an a nalogue of overt non-vocal behaviour and the latte r has been accepted (Hinde , 1969) as an index of motivatio nal state . The refore , since the cliff-nesting Kittiwake 's o vert di splays are less expa nsive yet the voca l behaviour appears to be mo re e la bo rate , it is li ke ly that voca l behaviour is used far mo re by cliff-nesting Kittiwakes as a means of communicating motivatio ns state . Wooller (1978) had shown that cliff-nesting Kittiwakes were a ble to recognise the ir partners, by voice alone and that the to ne and rhythm of individual Kittiwake's Long Call , the four syll able " Ki-ti-wa­a k" sound from which the bird de rives its names , di ffe red between individual birds. The ability to recognise a pa rtne r ca ll is o f o bvious importance in a de nsely crowded cliff colo ny where early in the breeding season as many as a thousand birds may be

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competing for nest-sites (e .g. in Puffin Gully) and partners. The Long-Call is used in at least seven different behavioural situations by the Kittiwake and of these , the most familiar is of course when it is used in the Greeting Ceremony, i. e . when following a per iod of separation partners will once on the nest-site, bow 8-10 times to each other whilst emittmg the Long Call , the ceremony is terminated by each bird tossing the bill into the vert ical position uttering a rapid " ak-ak-" sound called Upward Choking. In studying this particular behavioural Heath et al (1983), discovered that the length of the Greeting Ceremony was correlated with length of absence of one partner , in other words , the longer the period of separation the longer the Greeting Ceremony. However, as Daniels and Heath (in press) have observed , the Greeting Ceremony becomes truncated to occasionally only Upward Choking as the partners enter the Incubation stage of breeding when eggs a re present in the nest. A similar pattern persists throughout the Post-Incubation stage when chicks are present, but there is a gradual resurgence in the vigour of the Greeting Ceremony as the chicks develop and become more active.

The importance of vocal communication in the cliff-nesting Kittiwake have been emphasised by Danie ls et a! (1984) who showed that one of the calls, the Pre­Departure call , is a declaration of intended absence from the nest. This call is uttered by one partner prior to departure from the nest or nest-site . When this soft " powk­powk" sound is made it results more often than not in the voca lising bird leaving the nest/partner/eggs/chicks, but on some occasions the calling bird does not leave , Daniels et a l, revealed that non-departure was linked to the partners vocal reply . For example , if the Pre-Departure call was followed by ei ther Low Intensity Choking (an " i ee-ah ak " ) sound) or the Long Call , then the calling bird always departed , whereas if the partners response was Head Tossing (a high pitched tseep-tseep - sound reminiscent of food begging in the Kittiwake chick and often used by adult birds during Courtship Feeding) then the calling bird remained on the nest. So the former vocahsations sanction or condone absence whereas the latter inhibits or denies absence.

When a predator , such as a Greater Black Backed Gull (Larus marinus) or Peregrine Falcon (Fa/eo peregrinus), appear in the vicinity of a colony of cliff-nesting Kittiwakes, the entire colony emits a massive sound , here called the Antipredator Call. The Call appears to be a mixture of Long Calls , Bow-and-Moan and Flight Calling and is incredibly loud and is, of course , amplified by the narrow confines of the gully. No similar vocal behaviour has been reported in ground-nesting gulls and this particular behaviour may be a further adaptation by the cliff-nest ing Kittiwake .

Work is continuing on each of the ca lls identified and described by Daniels and Heath (ibid) and gradually the motivat ional basis and functional significance of the vocalisations are being discovered. Investigations continue on Lundy, but are now also being carried out in South Devon . Collaborative work has also been commenced with Dr. E . Danchin in Paris , and Dr. Jean-Yves Monnat at Brest.

TABLE I. The calls emitted by the cliff-nesting Kittiwake ( Rissa tridactyla)

Name of Call Downward Choking

Low Intensity Choking

Upward Choking

Jabbing

Head Tossing

Sound Emitted eh-uh; eh-uh

i-ee-ah-ak ; i-ee-ah-ak

ak-ak-ak-ak

rhythmic repetitive muffled Long-Call i-ee-a-a

tseep-tseep-tseep

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Function/Display distance reducing, attracts female

intersperses bouts of aggressive behaviour

terminates and occasionally substitutes for the Greeting Ceremony

distance increasing, used during standing attacks on neighbours

solicits courtship feeding

Head Shaking

Long Call

Bow-and-Moan

Flight Calling

Pre-Departure Call

Alarm Call

Anti Mass Predator Calling

REFERENCES

jik-jik-jik

ki-ti-wa-ak

rhythmic cooing sound

soft aspirant wailing

pohk-pohk-pohk

gak-gak-gak

entire colony erupts into loud cacophonous sound

emitted by male prior and during copul ation

(a) G reeti ng Ceremony and partner recognition (b) sanctions absence (c) soft sound made by parent when chicks a re present

defence of adopted territory

possibly an ae ri al continuation of Bow-and­Moan. Function unclear

signals intention to leave partner

signal possible danger

occurs in response to a predator in the gully. Not observed in grou nd-nesting Kitt iwakes

CULLEN, E. (1957) Ibis, 99, 275-302 . Adaptations in the Kittiwake to Cliff-Nesting. DANIELS , D . & HEATH , J. (1984) Devon Birds , Feb . issue. The Calls and

Displays of the Kittiwake Gull (Rissa tridactyla). DANIELS , D. , HEATH , J . & RAWSON , W. (1984) Animal Behaviour , in press.

A Declaration of Intent in the Kittiwake Gull (Rissa tridactyla). DANIE LS , D . & HEATH , J. (in prep.) Vocal behaviour in the cliff-nest ing

Kittiwake Gull (Rissa tridactyla). HEATH , J. et al. (1982) Beh. Anal. Lettrs., 2, 221-225. Duration of Vocal

Behaviour During the Greeting-Ceremony of the Kittiwake Gull (Rissa tridactyla) .

HINDE, R . A. (1969) Bird Vocalisations: The Relation to Current Problems in Biology and Psychology . N. Y: Cambridge University Press.

McLANNAHAN, H . M. C. (1973) Behaviour , 44(1-2), 36-88. Some aspects of the ontogeny of cliff-nesting behaviour in the Kittiwake (Rissa tridactyla) and the Hernng Gull ( Larus argentatus).

PALUDAN , K. (1955) Vedensk. Medd. fra Dansk. Naturh. Foren. , ll 7, 1-21. Some behaviour patte rns of Rissa Tridactyla.

WOOLLER, R . D. (1978) Z . tierpsycho l. , 48(1), 68-86. Individu~ l vocal recognition in the Kittiwake Gull (Rissa tridactyla).

ZAHA VI , A. (1982) Behaviour , 80(1-2), 1-8. The pattern of vocal signals and the information they convey.

ACKNOWLEDGMENTS The author wishes to thank : (I) The Lundy Field Society and the University of Exeter Research Fund , for

providing financial support without which this research programme could not have been initiated.

(2) Col. R. Gilliat for his help in providing accommodation and fac ilities for the research team.

(3) The men of Trinity House based at the South Light , Lundy , for data on wind , weather, tides, barometric pressure and water and air temperature .

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